Vaccines are an important means for preventing and/or treating a number of diseases and disorders (e.g., viral infection, bacterial infection, and cancer). Nucleic acid-based vaccines have several advantages over protein or attenuated-live vaccines. Introduction of a nucleic acid that expresses an antigen into a target cell allows for rapid development of vaccine that generates and immune response against an antigen of interest. For protein vaccines, an effective and efficient method of protein purification needs to be developed each time a new vaccine is created. For live vaccines, a method of attenuation needs to be identified that doesn't completely stop the growth of the pathogen, yet proven to be completely safe in humans. Development of protein purification and attenuation methodologies are extremely time-consuming processes. In contrast, most nucleic acid-based vaccines can be manufactured very quickly using the same manufacturing techniques each time with just a quick change in the nucleic acid encoding the antigen of interest. Replication incompetent adenovirus is one nucleic acid-based vaccine system which is rapidly, predictably, and inexpensively made at high titer [Polo, J. M. and Dubensky, T. W., Jr., Drug Discov Today, 7(13), 719-727 (2002)]. However, the efficiency of the antigen-specific response following administration of adenoviral vectors known in the art is low. Thus, there is a need in the art for new adenoviral vectors that can be used to efficientlyt elicit an immune response against an antigen of interest. The present invention satisfies these and other needs.